Stuffing box



J. LEROY STUFFING BOX Feb. 18, 1930.

Filed June 16. 9 2 Sheets-Sheet 1 fiver/f r. Ju/es Lam Z7 %Mmce Feb. 18,1930. J. LEROY 1,747,253

STUFFING BOX Patented Feb. 18, 1930 UNITED STATESYPATENT OFFICE JunieLEROY, or m GABENNE-COLOMJBES, ranion srurrmo 30::

Application filed June 18, 1921, Serial No. 478,080, and in France June20, 1920.

The present invention relates to a packing for all types of shafts butparticularly suitable for those to which an alternate rectilinear, thatis reciprocating, movement is imparted, for example as in piston rods,steam engine, locomotive or similar shafts.

For shafts which rotate but do not move longitudinally it is old to usepackings comprising bafiles between which thesteam expandsprogressively, but these packings are not applicable to reciprocatingshafts because a part of the elements forming the bafiles is integralwith the shaft, which hence cannot describe longitudinal movement.

The packing forming the subject of the present invention ischaracterized by the fact that it comprises a series of cups and inthese cups discs provided with projections of spe cial form, thesevarious elements being contained in a housing but resting freely on theshaft and adapted to move freely in the lateral direction with the shaftwithout causing the elements to wedge against the walls of the housing.

On the other hand, the discs provided with spacerscomprise groovesleading to the expansion spaces so as to avoid formation of gas veinswithout a certain pressure between the elements of the packing shaft.

The improved gas-tight stufling box forming the object of the presentinvention is of the kind of the stufiing box specified in my pendingapplication No. 395,338 filed July 10, 1920, now Patent Number1,514,057, issued Nov. 4, 1924, and has for its purpose to ensure at the1point where the piston rod traverses the stu ng box, a very effectivejunction in order to prevent leakages.

The object of the invention is illustrated in the accompanying drawingas follows:

Fig. 1 shows a sectional elevation of one of the constructions of theimproved system according to the present specification.

Fig. 2 shows a detail view inplan of one of the constituent elements ofthe system in question.

Fig. 3 shows a sectional elevation corresponding to Fig. 2.

Fig. 4 shows a plan view of another element forming part of the presentsystem.

Fig. 5 shows a sectional element correspon ing to Fig. 4.

Fig. 6 shows an elevation and longitudinal section of a modification ofthe construction in question.

Fig. 7 shows two sectional views made on the lines VIIVII and VII -VII'of Fig. 6.

Fig. 8 shows an elevation with a piece broken off of one of the elementsof the apparatus illustrated in Fig. 6.

Fig. 9 shows a sectional view correspondin to Fig. 8.

Feferring firstly to Figures 1 to 5 of the accompanying drawings:

These figures show in detail one of the constructions of the systemimproved according to the present invention. It will be seen that .thebottom of the cylinder is prolonged by means of a box 6 in which areplaced the elements forming the gas-tight stufling box, these elementsbeing pressed, under the action of a screw plug cl, against the part amounted upon the bottom of the cylinder in any convenient manner.

Supposing that in a certain case there is a leakage, or a condensationif it is a question of a steam engine; there has been provided upon thescrew plug (Z a series of little annular channels 6 and a deeper channelf forming a collecting receptacle and havlng for its object to collectany steam, condensed or otherwise, which may have been brought to it bythe piston rod 9. The steam or the Water resulting from its condensationcan then escape through the channel h which communicates with acondenser or other suitable apparatus. One may also provide an asbestoswasher i placed close to the outer end of the screw plug d, the saidwasher having for its object to prevent the carrying forward of thelubricating oil or of the water of condensation when the rod 9 isoperating its to-and-fro motion.

' Conformable to the construction above set forth, the discs or rings iswith apertures are formed in the following manner: In order to prevent.any breach of continuity and to compel the steam, the air or the gas topass b the apertures j of the rings k and to shape t ese rings inaccordanc with the arrow Z in place of passing directly along the trackof the arrow I, there is provided at the inner periphe of these ringsthe proJlectm parts m at, orming bafiles and supporte alternately by theone and the other faceof the rings is, and a circualr channel m whichhas for its object to break the current of air, gas or steam which mightpass between the baflles n, receiving the said rings and the rod g, thusforcing the gaseous'fluid to pass through the apertures j along thetrack indicated y the arrows l. The disks is, contained in the bafiies'n, are furnished on their two lateral faces with lugs m m spaced so asto have channels j between them; the lugs m of the one face, beingplaced opposite to the channels on the other face, and vice versa. Thelugs m m are furnished with grooves m, which, together with the wall ofthe spindle g, and the wall of bafiies n, form annular grooves,intercommunicating with the channels y', and communicating with thechannels with the space between the disks and ba es,. and the spindle g.Fluid, under some pressure, tends naturally to escape along the spindle9, between spindle g, and the metallic packing elements. Encountering,however, the channels 7', or the annular grooves m, it escapestherethrough, and travels under constantly reducing pressure around theedge of disk 70, as shown by arrow Z in Fig. 3. Accordingly, the fluid,under pressure, which normally would pass along the spindle g, is ledaround successive disks 7c which'constantly reduces its pressure. Theescaping fluid arriving, without pressure at the last bafiie n is unableto escape from the stufiin box. In the event that the rod g, instead 0having a linear alternating movement, should receive a continuouscircular movement (such as that of a turbine axle for instance) thesegments 0 and p arranged in the interior of the bafiies n might havethe tendency to turn along with the rod; they would then be displacedwith respect to one another because they are adjusted with slightfriction in the baflies n, and may take such a position that their slotsg and 1' would become coincident and thus give rise to a leakage. Inorder to prevent this drawback, a hole is cut on the contact line of thetwo segments, and there is placed in this hole a stud .9 made of a metalsofter than that of the bafiies n so as not to scratch these lattersupposing that the stud should project from t e segments.

It should further be observed that the ex- .ternal diameter of thebaffles 71. is slightly smaller than that of the container 6, whereasthe central aperture of these baffles provided for the passage of therod 9 is distinctly larger than the diameter of this rod, which permitsof the latter taking its place without pressing against the bafiies inthe case in which the centering has not been perfectly correct. The heiht of the parts 'm. and m of the rings is fi xed so that these rings canbe displaced with slight friction in the baflies nthe internal clearanceof the segments 0 and p is fixed so as to obtain a slight friction onthe rod g when this latter has reached its maximum stroke, the width ofthese segments being moreover determined so that they can move withslight friction in the bafiies n.

The number of the elements which form the gas-tight stufling box isvariable according to the pressure and the mode of operation of theengine, and the same applies to the intervals in the sequence ofarrangement of the bafile rings, at which these elements including thedouble segments recur.

Finally, it should be remarked that the gastightness of the stufiing boxis assured not by the contact between the bafiies n and the internalsurface of the enclosure 1) but by the contact of the baflles with oneanother.

In the modification shown in Figures 6 t0 9 of the drawings the systemof gas-tight stuinng always includes an enclosure b in which are mountedthe various elements which constitute the gas-tight stuifing boxproperly so called. These elements are likewise always formed of thebaflle n juxtaposed, and each having either a ring is or two segments 0and p pressing one upon another. The rings is always show projectingparts m m arranged alternately upon one or the other of their faces soas to form baflies, and a circular channel m having for its purpose tointerrupt the current of air, gas or fluid which may pass between thebafiie n and the piston rod 9, and which thus compels the aforesaidfluid to pass through the apertures j.

In the case of the modification in question, the totality of theelements of the stufling box is held in position within the enclosure 1)by means of the screw plug 1) which is screwed upon a correspondinglythreaded part I) placed for this purpose upon the end of the enclosure12 opposite the bottom of-the cylinder. At its other end the aforesaidenclosure has a threading t whereby it can be fixed upon the bottom ofthe cylinder, but such fixing might, of course, be effected in any othersuitable manner.

The enclosure 6 is provided with a grease duct a 11?, which is suppliedwith lubricant at the point u, either by a greasing vessel or by an oilsupply under pressure. The channel u terminates in a circular channel 0)which forms a reservoir for grease or oil all round the piston rod 9.

On the other hand, in order to prevent the lubricating material frompenetrating into the cylinder, the present improvement includes thedouble segment m m placed adjacent the channel '0, and a ring 3 whichkeeps it in place without obstructing it; the ring y is fixed by meansof a threading z in the enclosure 5 at the end of this latter which isfixed upon the cylinder.

tured to afford a free fit on the piston rod, the unoccupied chambersserving as expan- Finally, the segments 0, 32 arranged in the sionchambers and the lugged rings affording interior of the enclosure b inone or more baftortuous passages between said expansion fies n are soconstructed as to offer at 0 and 12 points at which they are split,which arrangement prevents any breakage.

The elements of the packing such as the discs is resting simply on theshaft and not being aflixed thereto, this shaft may describe anylongitudinal movement. On the other hand, the shaft may be movedslightly of! axis (this being inevitable) without the members of thepacking wedging against each other, by reason of the fact that the cupsas well as the discs may move laterally in their housing and follow themovements of the shaft.

It is to be noted on the other hand that the circular channels mprovided in the spacers m, m make it impossible for the' liquid underpressure to escape between the shaft and the members forming thepacking. It is known that packings formed of metallic bafie ele mentsoperated by successive expansion in spaces provided for this purposepermit the passage of small quantities of fluid; from baflie to bafliethe pressure of this fluid decreases progressively until it is too weakto flow to the outside in the last baifles of the packing. In packingsof the type above described it is possible that the fluid under pressurecan flow without expandin following the path of the arrows 2 Fig. 6)between the shaft and the discs; t is is prevented b the grooves m whichpresent an easier pat for the escape of the fluid under pressure; thefluid is in fact passed thereby to the spaces j comprised between thespacers or projectlons n, from which no escape in a dlrect line ispossible; all fluid tending to pass out is progressively expanded andchecked.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is A stuifing box for piston rods comprisin in combinationa casing adapted to surroun a piston rod, a plurality of bafiies havingperipheral flanges, said battles being arranged within said casing withthe flan e of each bafiie making contact with the ad acent baffleforming chambers between said baflies, said baflies being providedcentrally each with an aperture afi'ordin a free fit on the piston rod,means for pressing said baflies together in sealing relation at theircontact mg peripheral portions, and rings positioned in alternatechambers formed by said bafiles, said rings being of smaller diameterthan the radial dimensions of the chambers in which they are locatedandhaving lu' s alternating with restricted passages, on their oppositesides, extending substantially to the lateral walls of the chambers inwhich the are located, said rings being-also centrally aperchambers,deviating from the direct longitudinal leakage path along said pistonrod.

In testimony whereof I have signed my name to this specification.

JULES LEROY.

